"You cannot catch him - it's unbelievable how quick and how good with his feet he is," Mertesacker told Arsenal.com. "If you get one against one with him, it's nearly impossible.

"That was a really tough game for everyone today, especially in the first half. It was intense from the first minute and Chile played well over the 90 minutes. I think they are the toughest opponent we have played so far.

"I think we have a strong squad but not everyone is fit at the moment. It's really vital that we get together and that everyone is fit and aware of the situation when we meet up because we can get such opponents [like Chile] in the summer."